As methods for obtaining a molded article having a predetermined shape using thermoplastic resin, generally, there are various molding methods such as injection molding, blow molding, extrusion molding and press molding.
Aside from these general molding methods, Patent Document 1 discloses a method in which when a cavity of a molding die is filled with molten thermoplastic resin, the thermoplastic resin is irradiated with electromagnetic wave including a wavelength region of 0.78 to 2 μm through the molding die. According to this method, the thermoplastic resin is more strongly heated as compared with a molding die made of rubber due to difference in physical property between rubber configuring the molding dies and thermoplastic resin.
Patent Document 2 discloses that thermoplastic resin particles filled into a rubber cavity is irradiated with electromagnetic wave including a wavelength region of 0.78 to 2 μm, the thermoplastic resin is heated and melted and then, if a space remains in the cavity, the cavity is additionally filled with molten thermoplastic resin.